Pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension after bilateral lung transplantation

Case report

A 30-year-old woman suffering from diffuse interstitial lung disease underwent bilateral lung transplantation in 2008. A high-risk bilateral pulmonary embolism (PE) occurred in 2020 after deep venous thrombosis. After lysis (Endovascular System and oral anticoagulation), 1-year follow-up imaging showed a persisting thrombus-load (Fig. 1). Right heart catheterization (RHC) 18 months after PE showed s/m/dPAP of 51/34/25mmHg, PVR of 5.6WU and CO 4.43l/min. Echocardiography demonstrated right ventricular dilation with impaired radial and longitudinal function. She reported worsening dyspnea (NYHA III) and impaired lung function (FEV1 1.3 l, DLCO 43%, best post-transplant value: FEV1 2.44 l, DLCO 68%) without diagnosis of CLAD. CT-imaging showed organized thrombotic material in the right inferior lobe and left pulmonary artery (Fig. 1). In 2022, bilateral PEA under deep hypothermic circulatory arrest was performed. On the right, multiple segments were obliterated, whereas in the left main trunk a cone-shaped occlusion of the complete left main PA at the level of the anastomosis was resected in addition to peripheral lesions (Fig. 1 and 2). Histopathological evaluation revealed cartilaginous metaplasia of the tunica intima (Fig. 2). This phenomenon represents a vascular remodeling process in which chronic thromboembolic injury, inflammation, TGF-β1-mediated vascular smooth muscle cell transdifferentiation, and transplant-related stress collectively drive the formation of cartilage-like tissue, resulting in irreversible maladaptive remodeling and pulmonary hypertension.

The patient was extubated on the first postoperative day and discharged to rehabilitation after 14 days. After 7 weeks, she reported improved performance (NYHA I), and echocardiography showed decreased sPAP (from 45 to 37 mmHg). 18-month postoperatively the patient was in an excellent condition, reported further improvements in performance (NYHA I) and RHC showing s/m/dPAP of 30/19/11mmHg, PVR 4.1WU and CO 3.65l/min.